What rhetorical devices are used in the first sentence of this poem? What's the role?

Where is the poem?

But I think the first couplet and parallel prose are mostly figurative and easy to introduce lyricism, so metaphors are generally used. In fact, there are only a few rhetorical devices. I don't know what grade you are in, but you can write down the rhetoric and expressions that the Chinese teacher said in class. It's easy to do poetry appreciation.